Liquid micrometer-indicator.



P. G. PURINTON. LIQUID MIGROMBTBR INDIUATOR.

APPLICATION FILED FEB. 10, 1908. 4

Patented Nov. 17, 1908.

UNITED site` TEs PATENT oEEioE.

FORREST G. PURINTON. OF BEVERLY, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO PEB/LEY B. GLASS, OF BOSTON, MASSACHUSETTS.

LIQUID MICROIIETER-INDICATORv Speccaton or Letters Patent.

Patented Nov. 1'7, 190,8.

Application led February 10, 1908. Serial No. 415,058.

Beverly, in the county of Essex and State Eig.

'of Massachusetts, have Ainvented an Improvement in Liquid Micrometer-Indicators, of which the following description, in connect-ion with the accompanying drawing, is a specification,- like letters 'on the drawing representing like parts.

This invention relates to a micrometer indicator for test gages such as are used by machinists and others in testing with great accuracy a surface or line on the work.

The object of the invention is to provide an indicator which will readily and accu rately indicate to the eye very minute ditl'er ences in the work being tested, and for that purpose makes use of the movement of a iquid in a tube of small bore,as the indicating element. y

Theinvention will more fully appear from the accompanying description and drawings and will be particularly pointed out in the claims.

. The drawings represent preferred forms ofthe indicator and some of its adaptations. v In the drawings, Figure l is a view in perspective of a portion of a lathe, a piece of work therein to be tested, an ordinary form of testing gage, and the indicator 4of the `present invention adapted thereto, the supporting rod and clamp also being shown. 2 1s an elevation chiefly in longitudinal vertical cross section ot an indicator embodyi ingl the invention. Fig. 3 is alongitudinal vertical cross section o'a slightly different forni. Fig. 4; is an elevation: of the lower portion of the indicator embodying this invention showing an adaptation to the testing of vertical or similar surfaces. Fig. 5 is a detailv of'the supporting rod and clamp. Fig. 6 is a cross section through the tube and casing of the indicator shown in 3.'

F ig.,7 is a detail showing the adaptation ot a point to the indicator whereby the underneath surfaces of an object may be tested.

.'Fi'g. 8 is a `detail showing the adaptation of. ,a point to the indicator whereby interior surfaces may be tested..

The'indicator'ot' the present'invention is l adapted "to be'used with any of ,the wellknown `forms of surface gages, tool-posts, holders, Snel, by which work being operated upon by a lathe, planer, milling machine or in any other form may be tested, and it is therefore unnecessary to describe iu detail any of these well-known constructions. In Fig. l an ordinary form oflsuriace gage A is shown, provided with the adjustable holder B on which is mounted by means of a clamp C the supporting rod D. It will thus be seen that the supporting rod D by meanso't the clamp lC and the adjustment ot' the holder B on the base of the surface gage can be placed in any desired position. In the drawings the gage is shown as restingon a flat Surfaceron a lathe bed.

"As a suitable means for supporting the indicator of theprescnt invention in position for testing the work the supporting rod D is shown as provided with a clamp E which when set up by the setscrew E locks the base of the indicator fast to the supporting rod D'. But it will be obvious that the indicator may be supported in any suitable manner from any suitable gage.

The indicator itself in the form shownv in Fig. 2 comprises a base shown as made in two parts Fand F. The lower part of the base F is hollow at its upper end to receive the part F therein. It is also bored longitudinally and chamber-ed at its upper end at f to receive a sliding plunger G, having tast thereto at its upper end a plunger head G. The bore ot' the part F is madel slightly larger 'than the plunger G except atthe lower end, where it is contracted to provide' a bearing for the plunger. The head G of the plunger is freely movable inthe chamber f and `has a depending portion g which has a. bearing in` the base lpart f. It will thus be seen that the plunger GV moves freely and its only bearing points 'are near its upper and lower ends. The plunger is operated by lower end which prot-rudes the point at its` and which contacts with from the 'base F the work to be tested. work contacting pointis shown as an in tegral part of the plunger. The upper part 4F of the base is `'formed at its lower end to present a liquid reservoir H,opened at the bottom'andclosed partially at the top by the end of the tube K.

v A disk L ofA resilient material, such as rubber, is placed across the bottom of thc hollowl in the upper end of the part of the base over the ,head 4of Vthe plunger G and In' Figs. 1 to 4- the the pai-t F is screwed into the part F until its lower edge contacts with and locks the disk L against .the part F of the base so that the disk L forms the lower wall of the reser- E voir l-l.

The tube K is inade of glass and provided with a small 'uniform bore communicating with the reservoir H. Thetube is graduated throughout its length in any suitable manne-r, the graduations indicating for example' thousandths of an'inch. The tube is held in place in the part F of the base in any suitable way as by cement K.

.The reservoir H is filled with a suitable liquid, as for example mercury, and'when thel plunger of the indicator is in its normal position the mercury will till the reservoir and rise from the point K to the zero point of the graduations. If, now, the plunger G be raised by having its work contacting point brought into contact with the work to be tested the head Gr of the plunger will force in the resilient wall of the reservoirl, thus diminishing the size of the reservoir and causing the liquid to rise in the `tube and as the irregularity being tested diminishes the plunger will be lowered, correspondingly increasing the size of the reservoir H and lowering the liquid in the tube.l

The parts are solproportioned that each increment of movement of the plunger G produces a uniform change in the size of the resei'.voii',`and consequently the graduations on the tube may be made equal, or if the parts arev so constructed that there is any' "variation in the relation between the movement Aof the plunger and the change of the `size of the reservoir, then the gi'aduatioiis on the tube-may be calibrated to correspond therewith:A

Since the Aupper end of the tube is open either the indicator must be maintained in such aii erect position that the liquid will not run out, or else the resiliency of the disk L must be such as to countei'balance the Weight of the liquid. In the case of heavy liquids, such as mercury, the regulating of the disk L so as to counterbalance the weight of the liquid will usually interfere with thc free and ready movement of the plunger which is desired for securing very tine and accurate indications. Hence the construction shown in Fig. 3 is 'provided wherein a `light liquid, or a liquid of low specificof.v the""liiqf'iid" used and prevent the liquidA running out from the end of the tube. This regulation may be made in any suitable way,

l as for example by cutting ott the upper end i of the part F2 against which the head (1" of l the plunger G rests..

In Figs. 3 and G a shell'or guard M is shown as surrounding the tube K, and this may be used in any construction of the indicator to protect the glass tube. The shell may be secured in place by the cement li which holds t-he tube in place.

Then the gage is to be used for testing a vertical surface the tube of the indicator may be bent at right-angles, as indicated in Fig. fl. A

lVhen the gage is to be used for testing underneath surfaces a work contacting point, such as illustrated in Fig. 7 may be attached to the lower end of the base of the indicator. This point comprises a. socket O with a lever F fulcruined thereon, one arm of the lever contacting with the surface to be tested and the opposite arm contacting with the plunger.

Vhen the gage is to be used for testi-ng interior surfaces a work contacting vpointl such as shown in Fig. 8 may be attached to the lower end of the plunger. rl`his point is the same in principle, embodying a socket hole and a lever P of another order.

Having described my invention, what l claim as new and desire to secure by Letters Patent, is:

l. A micrometer indicator for test gages, comprisingabase, one part of said base being bored longitudinally, a plunger mounted to slide freely in said base, another part of said base being provided with chamber, a resilient memberbetween the said base parts adapted when in position to form one. wall of said chamber and to be acted upon by the end of said plunger, a graduated tube of small bore attached to the base and communicating with said reservoir, whereby upon the movement of the plunger the liquid is caused to iisc and fall in the tube and indicate the extent of movement of the plunger.

2. A micrometer indicator for test gages, comprising a base, one part of said base being bored longitudinally, a plunger mounted to slide freely in said bore and provided with a head, another part of said base being provided with a chamber, a resilient disk between the said base parts adapted when in chamber and to be .acted upon vby said bore attached to the base and cominuiiicating with said reservoir, whereby upon the movement of the plunger the liquid Vis caused extent of movement of the plunger.

3. A micrometer indicator for test gages, comprising a base, one part of said' base its lower end being of less diameter than at its central portion to form a bearing and being of larger diameter at its upper end position to form the lower wall of said plungerhead, a graduated tube of small being bored longitudinally, the saidbore atto rise and fallin the tube and indicate the d y ing at the lower end of the tube und the head o" the plunger sliding in the hearing ut the upper end of the tube, mother part ol smul buse bemg vprovlded Wu'h a chamber, a rendaptecl when in position to vform 'the lower munlealing with Suid reservoir, \\'hereh \"z upon the movement of the plunger the hqi'ud 1s caused fo use and fall 1n thetube und ln- 15 diente the exteni of movementv of the plunger.

wall of said ehqlnber anal to be neierl upon by said plunger head, n graduated lube of small bore attached to the buse and 00u1- l'n `testi1nony whereof, l have signed my uzune to thib speeil'mton, in the presence of two subsorlblng wuuesses. silient disk between the sald base parts FORREST G. PURI'NTON.

'WitnesSesz M'AuEL PAuTELow, EDWARD F. ALLEN. 

